Flu likes the weather humid and rainy

MANILA, Philippines - Flu viruses prefer the weather either cold and dry or humid and rainy, according to an analysis of climate variables and flu patterns around the world.

Researchers from several United States universities and the National Institutes of Health reached this conclusion primarily by studying flu and climate data from 78 sites in 40 countries worldwide, including the Philippines.

The study, published in PLOS Pathogens, found that in temperate zones, lower humidity and temperature would mean influenza peak activities. But while humidity remains a driver in the tropics, rainfall plays a significant role because in places like the Philippines and Vietnam, where there are intense monsoon rains, flu season peaks when it’s humid and rainy.

“Seasonal flu is an extremely contagious viral disease. Being cooped up indoors, where the virus from others who are sick may be transmitted, only increases the risk. So it’s no surprise that the rainy season, when many people spend lots of time staying indoors, marks the unofficial start of flu season,” explains Dr. Josefina Cadorna-Carlos, professor at the University of the East-Ramon Magsaysay Memorial Medical Center College of Medicine.

The most conducive places for spreading infection would be work places, schools, day care centers, and areas where there is crowding like shopping malls, cinema, and concert venues.

Carlos, also a pediatric infectious disease specialist, explains that flu infection will occur if the other person breathes in the infected person’s droplets that are suspended in the air or by touching items and surfaces contaminated with the flu virus and then subsequently touching their mouth, nose, or eyes.

Flu virus-laden droplets may remain infectious for several hours to even days, depending on where they fall. For example, influenza A virus will generally remain active longer on stainless steel, plastic, and similarly smooth and rigid surfaces (tabletops, doorknobs, keyboards, etc.) as compared to porous  surfaces.

“Getting the annual seasonal flu vaccine — either the quadrivalent or the trivalent formulation — is the best way to reduce the chances that one will get seasonal flu and spread it to others. When more people get vaccinated against the flu, less flu can spread through that community,” Dr. Carlos suggests.

Since flu activity here in the Philippines most commonly peaks in June and continues to occur as late as November, Carlos says children as young as six months, elderly individuals, and those in between these age groups, should have themselves vaccinated.

“This year’s flu vaccine, especially the quadrivalent one, offers a broader protection, since it is designed to protect against four different flu viruses — two influenza A viruses and two influenza B viruses,” says Carlos.

Apart from getting vaccinated, regular washing of hands is the next best way to avoid spreading infection. Carlos reminds everyone never to rub your nose or put your hands in your mouth without washing your hands first.

Of course, it also helps if one’s immune system is in tip-top shape. “Our body’s immune system is more powerful than we probably imagine and does a remarkable job of defending us against disease-causing microorganisms. Keep it in tip-top shape by choosing a balanced diet of lean cuts of meat, as well as other protein sources like beans, soy, and seafood; getting a healthy serving of  fruits and vegetables each day; cooking with olive or canola oils; limiting your alcoholic drinks; taking at least a 10-minute walk a few times a day; getting some sunshine (to get vitamin D); and perhaps the most important, reducing your stress levels through yoga, hiking, deep breathing or just listening to your favorite music,” Dr. Carlos prescribes.